1. Field of the Invention
The present invention relates to techniques for accessing web pages. More specifically, the present invention relates to a method and an apparatus for reducing the latency involved in retrieving web page components.
2. Related Art
The Internet presently enables a user with a simple Internet connection to navigate through millions of web sites containing media-rich web pages. However, not every Internet connection is created equal. Although connection speeds have been constantly increasing (e.g., from a 14.4 kbps dial-up connection to a 256 kbps DSL connection), other factors may still adversely affect the performance of Internet applications. In particular, latency plays a critical role in loading web pages. Web pages containing a large number of components (such as images) may suffer significantly from the latency involved in retrieving these components. This is because a web browser needs to download each component individually, and each download involves at least a round-trip delay between the browser and the server to set up a temporary connection (such as a TCP or a UDP connection). Furthermore, a web browser can only transfer a limited number of components concurrently.
This latency-prone component-retrieval process can significantly impair browser performance over connections with long latency. One such example is broadband satellite Internet connection, as shown in FIG. 1. Satellite Internet connections are capable of providing very high bandwidth. Unfortunately, the high altitude of geosynchronous satellites (more than 20,000 miles above the earth) creates a long round-trip delay between a client (browser) and a server. This latency is typically several hundred milliseconds. If we assume that a satellite Internet connection has a round-trip latency of 500 ms, and that a browser can at most transfer four components at a time, loading a web page with 100 components requires at least 12 seconds! Note that the fast data transfer rate provided by a satellite connection cannot reduce this latency, because the latency is determined by the physical distance the signal has to travel. This can result in a very frustrating experience for a user with a satellite broadband connection, because his high-bandwidth connection can have a worse performance than that of a dial-up connection.
Hence, what is needed is a method and an apparatus for reducing the latency involved in retrieving web page components.